Robot arm with impact absorption structure

ABSTRACT

A robot arm has an impact absorption structure for absorbing impact energy caused by a collision to protect a person from injury and the robot arm from being damaged. The robot arm includes a plurality of rigid beams provided at both end portions thereof to define a frame of the robot arm, and side members made of an elastic material and provided between the plurality of rigid beams to define an appearance of the robot arm and absorb the impact energy. Each side member includes a sheet made of a plastic material, a foam or honeycomb structure, and a fiber reinforced composite material attached to the sheet.

PRIORITY CLAIM

This application claims under 35 U.S.C. § 119 the benefit of the filing date of Oct. 1, 2003 of Korean Application No. 2003-68433, the entire contents of which are incorporated herein by reference.

BACKGROUND

1. Technical Field

The invention relates generally to a robot arm which absorb impact energy caused by a collision, thereby protecting a person from injury and specific parts of the robot arm from being damaged or broken. More particularly, the invention relates to a robot arm with an impact absorption structure in which a replaceable part is deformed by impact energy rather than other parts of the robot arm.

2. Background Information

Generally, robots have been used in a variety of industrial fields. Industrial robots have been used in various places where it may be dangerous to humans or it is impossible for humans to work, for example, clean rooms, a universal space and atomic furnaces, etc. Furthermore, there are robots which have been used in rehabilitation for patients and for the betterment of living or for leisure to improve and enjoy the life. The conventional robots have been gradually more intimate in their association with people.

The conventional robots are generally produced to have a strong structure to enhance their weight-support abilities. Particularly, robot arms are made of thick and massive metals to enhance the weight-support abilities. When the conventional robot arm is involved in a collision, a person may be injured, or a surrounding structure may be damaged. Further, the robot arm may be badly damaged at the joint parts or drive parts. Because the conventional robot arm is made of the metal, it requires a variety of processes, thereby complicating its manufacturing process. The conventional robot arm is problematic in that processing costs and production costs increase.

To solve the foregoing drawbacks, it is required that a robot arm has an impact absorption structure as well as the strong structure for the desired weight-support ability. This allows a robot arm to effectively respond undesirable motions and prevent safety hazards from being caused by the robot arm. Specifically, when a robot arm collides with a person or a surrounding structure, a certain part of a robot arm rather than a person or a surrounding structure should be easily deformed or broken. Therefore, a person is protected from injury and specific parts of the robot arm can be protected from being damaged.

SUMMARY

An object of the invention is to provide a robot arm with an impact absorption structure which has a sufficient strength to support its structure, and in which a predetermined part of the robot arm is easily deformed or broken by impact energy higher than a predetermined level, thereby preventing safety hazards.

In one embodiment, a robot arm with an impact absorption structure is provided that absorbs impact energy caused by a collision, thus protecting a person from injury and protecting specific parts of the robot arm from being damaged or broken. The robot arm includes a plurality of rigid beams provided along longitudinal edges of the robot arm to define a frame of the robot arm, and a side unit made of an elastic material and provided between the plurality of rigid beams to define an appearance of the robot arm and to absorb the impact energy. The side unit includes a sheet made of a plastic material, a foam or honeycomb structure, and a fiber reinforced composite material attached to the sheet.

In another embodiment, a robot arm includes a plurality of blocks made of a rigid material, and a connecting unit to connect one block to another block, thereby defining an appearance of the robot arm with the plurality of blocks connected to each other. The connecting unit is deformed by a force higher than a predetermined level, and includes a sheet made of a plastic material, a foam or honeycomb structure, and a fiber reinforced composite material attached to the sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views.

FIG. 1 is a latitudinal sectional view showing a construction and operation of a robot arm, according to a first embodiment;

FIG. 2 is a latitudinal sectional view showing a construction and operation of a robot arm, according to a modification of the first embodiment of FIG. 1;

FIGS. 3 a through 3 c are perspective views showing a construction and operation of a robot arm, according to a second embodiment, wherein:

FIG. 3 a is a perspective view of the robot arm, in which a plurality of blocks are separated from each other;

FIG. 3 b is a perspective view of the robot arm, in which a connecting unit connects one block to another block; and

FIG. 3 c is a perspective view of the robot arm, in which the connecting unit is deformed by impact energy applied to the block;

FIG. 4 shows a process of manufacturing a side unit of the robot arm of FIG. 1 or a connecting unit of the robot arm of FIG. 3;

FIG. 5 shows another process of manufacturing the side unit of the robot arm of FIG. 1 or the connecting unit of the robot arm of FIG. 3;

FIG. 6 shows a molding process of the side unit or the connecting unit of the FIG. 4 or 5; and

FIG. 7 shows another molding process of the side unit or the connecting unit of the FIG. 4 or 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, embodiments of a robot arm will be described in detail with reference to the attached drawings.

FIG. 1 is a latitudinal sectional view showing a construction and operation of a robot arm 10, according to a first embodiment. FIG. 2 is a latitudinal sectional view showing a construction and operation of a robot arm 10, according to a modification of the first embodiment of FIG. 1. FIGS. 3A through 3C are perspective views showing a construction and operation of a robot arm 10, according to a second embodiment.

As shown in FIG. 1, the robot arm 10 according to the first embodiment includes a plurality of rigid beams 30 which are provided along longitudinal edges of the robot arm 10. The robot arm 10 further includes a plurality of side units 20 which are respectively provided between the pluralities of rigid beams 30. The plurality of rigid beams 30 defines a frame of the robot arm 10, and the plurality of side units 20 defines an appearance of the robot arm 10. Outer surfaces of the robot arm 10 except for the longitudinal edges are surrounded by the plurality of side units 20 which are exposed to an outside of the robot arm 10. Each of the side units 20 comprises a foam structure and a fiber reinforced composite material. Generally, the fiber reinforced composite material has a different strength according to directions. In the robot arm 10, the robot arm 10 with the plurality of side units 20 has a higher strength in a longitudinal direction and has a lower strength in a latitudinal direction. Due to the above-mentioned construction of the robot arm 10, when external impact is applied to the robot arm 10 in the latitudinal direction, the side unit 20 of the robot arm 10 is deformed inwardly to absorb impact energy, as shown in FIG. 1. Therefore, when the robot arm 10 collides with a person or a surrounding structure, the plurality of side units 20 absorb the impact energy caused by the collision. Thus, the robot arm 10 protects the person from injury and protects the surrounding structures and specific parts of the robot arm 10 from being damaged or broken.

As shown in FIG. 2, a robot arm 10′ is modified to include a plurality of side units 20′ which have corrugated surfaces 21 to enhance the impact-absorbing ability of the robot arm 10′. Each of the side units 20′ with the corrugated surface 21 has a surface area larger than the side unit 20′ of FIG. 1, which does not have any corrugated surface. Therefore, the side unit 20′ with the corrugated surface 21 is easily deformed in response to external impact, thus enhancing its impact-absorbing ability.

The robot arm 10′ may have a rigid body to absorb the impact energy, different from the robot arm 10 shown in FIG. 1. FIGS. 3 a through 3 c are perspective views showing construction and operation of a robot arm 110, according to a second embodiment. FIG. 3 a is a perspective view of the robot arm 110, in which a plurality of blocks 40 are separated from each other. FIG. 3 b shows the robot arm 110, in which a connecting unit 41 connects one block 40 to another block 40. FIG. 3 c is a perspective view of the robot arm 110, in which the connecting unit 41 is deformed by impact energy applied to the block 40.

The robot arm 110 according to the second embodiment includes the plurality of blocks 40, and the connecting unit 41 to connect the plurality of blocks 40 to each other. Each of blocks 40 may have the same sectional structure as the robot arm 10, 10′ of the first embodiment shown in FIG. 1 or 2. The plurality of blocks 40 are connected to each other by the connecting unit 41. The connecting unit 41 comprises a foam structure and a fiber reinforced composite material in the same manner that is described for the side unit 20 of the robot arm 10 according to the first embodiment.

Each of the blocks 40 of the second embodiment is made of a metal, so that a shape of the blocks 40 of the robot arm 110 is not easily deformed or broken regardless of external impact applied to the blocks 40. On the other hand, the connecting unit 41, which connects the plurality of blocks 40 to each other, has a high elasticity and strength lower than the blocks 40. When external impact lower than a predetermined level is applied to one of the plurality of blocks 40, the connecting unit 41, which has the strength higher than the block 40, is deformed or broken as shown in FIG. 3 c. The connecting unit 41 absorbs impact energy applied to the block 40, thereby protecting the blocks 40 or a joint part 42 which is difficult to replace and is expensive to manufacture. In the meantime, the fiber reinforced composite material of the connecting unit 41 has a different strength according to the directions in the same manner as that described for the side unit 20 of the first embodiment. Thus, a manufacturer must consider the above-mentioned specific characteristics of the fiber reinforced composite material while attaching the fiber reinforced composite material on the connecting unit 41.

FIG. 4 shows a process of manufacturing the side unit 20 of the robot arm 10 of FIG. 1 or the connecting unit 41 of the robot arm 110 of FIG. 3. FIG. 5 shows another process of manufacturing the side unit 20 of the robot arm 10 of FIG. 1 or the connecting unit 41 of the robot arm 110 of FIG. 3. FIG. 6 shows a molding process of the side unit 20 or the connecting unit 41 of the FIG. 1 or 3. FIG. 7 shows another molding process of the side unit 20 or the connecting unit 41 of the FIG. 1 or 3.

As shown in FIGS. 4 through 7, the side unit 20 of the first embodiment or the connecting unit 41 of the second embodiment comprises a sheet 50 to define shape of the side unit 20 or the connecting unit 41. The sheet 50 is made of a foam or honeycomb structure. The foam structure is a porous structure which is made by foaming a plastic material, such as urethane, polymethacrylimide(PMI), polyvinylchloride(PVC), acrylonitrile-butadiene-styrene(ABS), phenol and etc. The honeycomb structure is that a material, such as paper, aramid, aluminum and etc., is formed to have a honeycomb pattern before being coated with a resin material. The molding process of the sheet 50 of the robot arm 10 will be described below, in particular, where the sheet 50 comprises the foam structure.

As shown in FIG. 4, the robot arm 10 includes a plurality of mounting pieces 70 that are mounted on the sheet 50. To mount the plurality of mounting pieces 70 on the sheet 50, two methods may be used. First, a plurality of grooves 51 may be provided on the sheet 50, so that the plurality of mounting pieces 70 is respectively inserted into the grooves 51. Alternatively or additionally, the plurality of mounting pieces 70 may be attached on an outer surface of the sheet 50. After the plurality of mounting pieces 70 are mounted on the sheet 50, a plurality of fiber reinforced composite materials 60 may be attached on the sheet 50. The plurality of fiber reinforced composite materials 60 are cut to expose the plurality of mounting pieces 70 to an outside of the sheet 50. Preferably, the fiber reinforced composite materials 60 remains a soft state prior to the attachment on the sheet 50, because it is very difficult to process the fiber reinforced composite material 60 once it is hardened. However, as shown in FIG. 5, if the soft fiber reinforced composite material 60 is not prepared, the manufacturer cuts the hardened fiber reinforced composite material 60 to provide a plurality of pieces, prior to attaching the fiber reinforced composite materials 60 on the sheet 50. Thereafter, the manufacturer attaches a laminated sheet 80 on the fiber reinforced composite materials 60. The above-mentioned method has advantages that production costs are substantially reduced by using the fiber reinforced composite material 60, available in open market, without any additional process.

As shown in FIG. 6, the sheet 50, on which the fiber reinforced composite materials 60 are attached, is inserted into a mold 100, prior to tightening the mold 100 with bolts or clamps to compress the sheet 50 under a sufficient pressure. The mold 100 is thereafter heated, taking into consideration thermal capacities of both the robot structure and the mold 100. The sheet 50 and the fiber reinforced composite materials 60 have thermal expansive coefficients higher than that of the mold 100, so that pressure in the mold 100 is increased in response to an increase in the temperature of the mold 100. Thus, the fiber reinforced composite materials 60 are hardened and attached to the sheet 50 in a compression state. The above-mentioned process of hardening and attaching the fiber reinforced materials 60 to the sheet 50 is so-called a simultaneous hardening process. As shown in FIG. 7, the robot arm 10 may further include a porous thin sheet 65, which is provided on the fiber reinforced composite material 60 to enhance an impact-absorbing ability of the sheet 50. As described above, the sheet 50 of the robot arm 10, produced by the simultaneous hardening process, does not require an additional post-process, thus reducing its processing costs. Furthermore, because the fiber reinforced composite materials 60 having a higher strength is hardened, and, simultaneously, attached to the sheet 50, an additional attaching process is not required.

Since the sheet 50 is made of the soft material, such as the foam or honeycomb structure, and the fiber reinforced composite material 60, surrounding the sheet 50 is not easily processed, it is very difficult to mount separate components on the sheet 50. Therefore, the mounting pieces 70, made of a metal or an industrial plastic material which has a predetermined strength and is possible for machine work, are mounted on the sheet 50, so that the desired additional components, such as a sensor, a hydraulic apparatus, etc., are mounted on the mounting pieces 70. Alternatively, the sheet 50 of the robot arm 10 is easily coupled to a robot.

As described above, a robot arm with an impact absorption structure is provided that absorbs impact energy caused when the robot arm collides with a person or a surrounding structure, thereby protecting a person from injury and preventing a surrounding structure from being damaged. In addition, specific parts of the robot arm are protected from damages.

It is therefore intended that the foregoing detailed description be regarded as illustrative rather than limiting, and that it be understood that it is the following claims, including all equivalents, that are intended to define the spirit and scope of this invention. 

1. A robot arm having an impact absorption structure for absorbing impact energy caused by a collision, comprising: a plurality of rigid beams provided at both end portions of the robot arm to define a frame of the robot arm; and side members made of an elastic material and provided between the plurality of rigid beams to define an appearance of the robot arm and to absorb the impact energy, each side member including: a sheet made of a plastic material and having a foam or honeycomb structure; and a fiber reinforced composite material attached to the sheet.
 2. The robot arm according to claim 1, wherein each side member has a corrugated surface.
 3. The robot arm according to claim 1, wherein each side member is made by a simultaneous hardening process and includes: a hollow core member being made of the sheet , and having a plurality of grooves provided thereon.
 4. The robot arm according to claim 3, wherein each side member further includes: a mounting piece inserted into each of the grooves of the hollow core member and made of a material suitable for machining work; and a rigid structural member including the fiber reinforced composite material and attached to each of upper, lower, left and right side surfaces of the hollow core member, the rigid structural member having an opening provided thereon to expose the mounting piece to an outside of the rigid structural member.
 5. A robot arm having an impact absorption structure for absorbing impact energy caused by a collision, the robot arm comprising: a plurality of block members made of a rigid material and connected with each other; and connecting members for connecting one block member to another block member to define an appearance of the robot arm, each connecting member being deformed by a force stronger than a predetermined level, each connecting member including: a sheet made of a plastic material and having a foam or honeycomb structure; and a fiber reinforced composite material attached to the sheet.
 6. The robot arm according to claim 5, wherein each connecting unit is made by a simultaneous hardening process and includes: a hollow core member being made of the sheet and having a plurality of grooves provided thereon.
 7. The robot arm according to claim 6, wherein each connecting unit further includes: a mounting piece inserted into each of the grooves of the hollow core member and made of a material suitable for machining work; and a rigid structural member including a fiber reinforced composite material and attached to each of upper, lower, left and right side surfaces of the hollow core member, wherein the rigid structural member has an opening provided thereon to expose the mounting piece to an outside of the rigid structural member.
 8. The robot arm according to claim 7, further comprising: a porous sheet provided between the hollow core member and the rigid structural member. 